4s-fe Ecu Pinout [patched] Jun 2026

The Toyota 4S-FE is a 1.8-liter, inline-four internal combustion engine belonging to the reliable S-engine family. Produced from the late 1980s through the late 1990s, it powered popular Japanese domestic market (JDM) models like the Toyota Corona, Carina, Chaser, Cresta, and Mark II.

: Injector Pulses. Controls the opening of the fuel injectors. typically fires injectors 1 and 3, while fires injectors 2 and 4. 4s-fe ecu pinout

Always disconnect the negative battery terminal before cutting, pinning, or soldering any wires near the ECU. A short circuit can destroy the internal microprocessors. The Toyota 4S-FE is a 1

This plug delivers main battery voltage, ignition switched power, and critical sensor grounds. Description Wire Function / Target Switched Power +12V from the EFI Main Relay +B1 Switched Power Backup Secondary +12V from EFI Main Relay BATT Constant Battery Power Permanent +12V for ECU memory (EFI Fuse) E1 Engine Ground Main chassis and engine block ground connection E2 Sensor Ground Clean ground loop return for engine sensors E01 / E02 Power Grounds High-current grounds for injectors and idle valve IGSW Ignition Switch Signals the ECU that the key is in the "ON" position Plug B (Engine Sensors & Signals) Controls the opening of the fuel injectors

If you are diagnosing a "crank, no start" condition on your 4S-FE, grab a digital multimeter and perform these checks at the ECU pins:

| Pin | Type | Signal Name | Function | |:---:|:---:|:---:|:---| | 3 | Input | | Engine Coolant Temperature Signal | | 5 | Input | THA | Intake Air Temperature Signal | | 4 | Input | PIM | Intake Manifold Pressure Signal (for some markets) | | 7-8 | Input | VTA / VCC | Throttle Position Sensor Signal | | 9 | Input | NE | Crankshaft RPM Signal (from distributor) | | 21 | Input | NE (Alt.) | RPM Signal (alternate pin) | | 10 | Input | OX | Oxygen Sensor (Lambda) Signal | | 23 | Input | KNK | Knock Sensor Signal | | 16 | — | E2 | Sensor Ground (return for sensors) | | 24 | Ground | E1 | Computer Ground (main ground) |